Zhejiang University has prepared ultra strong and tough 3D printing elastic materials

Professor Xie Tao and researcher Wu Jingjun from the School of Chemical Engineering and Biotechnology at Zhejiang University have designed a new type of photosensitive resin and used it to create a "super rubber band" that can stretch to over 9 times its own length and lift 10 kilograms of objects with a "body" with a diameter of 1 millimeter through 3D printing. The relevant results were recently published in the international academic journal Nature.

Comparison diagram of "Super Rubber Band" before and after stretching. The left image shows before stretching, and the right image shows after stretching. Research team provides images

Different from the layer by layer printing method, UV cured 3D printing technology is like printing photos, using ultraviolet laser to cure photosensitive resin. The product is "exposed" and "developed" from the printing material, making the printing process faster and closer to industrial application standards. However, UV cured 3D printed products are often brittle and prone to breakage, mainly used for printing models and not suitable for scenarios with high mechanical performance requirements.

"In order for 3D printing technology to adapt to more scenarios, it is necessary to change the material properties," said Fang Zizheng, the first author of the paper and a researcher at the Hangzhou International Science and Technology Innovation Center of Zhejiang University. The research team first focuses on the reactivity and flowability of the material during the printing stage to meet the requirements of material forming, and then performs toughening treatment after printing and forming.

Fang Zizheng said that the team added dynamically hindered urea bonds, polyurethane segments, and carboxyl groups to existing photosensitive resin molecules. During the stage of printing precursor materials, they are in a "latent" state. After printing, the finished product will be transferred to a 90 degree Celsius "oven" and left to stand for a while, and the molecular structure and properties of the material will quietly change.

It is understood that researchers printed a "rubber band" using this new type of resin and conducted endurance tests on it. Experiments have shown that rubber bands can be stretched to 9 times their own length and withstand a tensile force of 94 megapascals without breaking. In addition, researchers have also used this material to prepare balloons and other objects with excellent puncture resistance.

Wu Jingjun stated that the strength and toughness of this photosensitive resin material far exceed similar materials reported in existing literature and commercial products. This research progress brings dawn to the breakthrough of material limitations in 3D printing technology and its large-scale application in high-performance product manufacturing.

Source: Science and Technology Daily